Genetic Relatedness of Candida albicans in Oral Commensalism and Disease. Mucocutaneous infection with Candida albicans has long been recognized as an important disease often occurring in individuals who are predisposed to opportunistic pathogens by underlying disease (eg. HIV infection, diabetes), age extremes, or immunosuppressive medications. While the existence of these fungi in the oral cavity as commensals is widespread, it is not known whether clinical candidosis is a function of specific pathogenic strains, or the ability of many strains to become pathogenic through in vivo genetically controlled phenotypic switching in oral disease. Recent studies have shown that Candida strains isolated from various body locations can exhibit different switch phenotypes, and the trait of switching may therefore play an important pathogenic role. This proposal will include the isolation of oral Candida from healthy and diseased human subjects using standardized culturing procedures, followed by the identification of each isolates switching repertoire. In addition, DNA electrophoretic profiles for each isolate will be completed through Southern Blot hybridization using an available DNA probe. This will allow for critical comparisons between isolates, and a comparison of genetic relatedness with switching repertoires identified from these oral isolates in health and disease. Therefore, the proposed research will provide new information for understanding the relationship of oral Candida isolates in commensalism versus disease in order to identify whether or not specific strains are linked with pathogenicity.